Ashlee Simpson Becomes Ashlee Wentz

“I think that that’s something that a woman should do when they’re marrying a man,” she tells PEOPLE. “It’s a tradition that I think is a great tradition.”

The singer, whose May 17 wedding featured an Alice in Wonderland-themed reception, says that privately she’ll go by Ashlee Wentz and professionally she’ll be Ashlee Simpson-Wentz.

Pete Wentz says he left the name change decision to his wife. “These decisions with Ashlee and her name are all completely up to Ashlee,” Wentz says. “I want her to do these kinds of things the way she wants to do them.”

Still, he admits, he was flattered. “Oh man, I was like upgrade me! You know what I’m saying? The Wentz family, our Christmas card just got upgraded!” he says. “It feels insane. It feels unreal.”